Johannes Pfau wrote:
struct CString(T)
if (isSomeChar!T)
{
T* str;
}
@property
auto cstring(S : T*, T)(S str)
if (isSomeChar!T)
{
return CString!T(str);
}
string test = "abc";
immutable(char)* p = test.ptr;
writefln("%s", p.cstring); // prints "abc"
Here the char pointer type is "annotated" as null terminated string
and writefln can use this information.
If CString implemented a toString method (probably the variant taking a
sink delegate), this would already work.
I reworked this example to form a forward range:
http://dpaste.dzfl.pl/7ab1eeec
The major advantage over "%zs" is that it could be used anywhere, not
only with writef().
For example C binding writers may change:
extern(C) char* getstr();
to
extern(C) cstring getstr();
so the string may be immediately used with writef();
> I'm not sure about performance
> though: Isn't writing out bigger buffers a lot faster than writing
> single chars? You could print every char individually, but wouldn't a
> p[0 .. strlen(p)] usually be faster?
I think it internally prints single characters anyway. At least it must
test each character if it's not zero valued. strlen() does that.
